Just stumbled across this YouTube channel that popped into my suggestions. These guys apparently travel to historic battlegrounds and use metal detectors to search for left out belongings and military ordenance. In this video they look around the Ardennes forest and find a defused pineapple grenade, empty Browning (50 calibre) shells and a full M1 Garand clip with live ammunition. In the end they find something cooler, but Iām not going to spoil it 
The channel seems cool, I subscribed!